The present invention relates to a fuel composition containing a fatty acid alkoxylate and a nitrogen containing detergent as a method to remedy engine intake valve sticking.
Hydrocarbon fuels generally contain substances that tend to form deposits in the fuel delivery system of an internal combustion engine such as the fuel injectors in diesel engines and the intake valves in gasoline engines. These deposits, if allowed to build up, can significantly reduce engine performance in terms of drivability, power output, fuel economy and exhaust emissions. It is highly desirable to incorporate detergents into hydrocarbon fuels that are effective in controlling deposits by inhibiting their formation and facilitating their removal so that engine performance is maintained or improved.
However, it is also known that these detergent additives which remove carbonaceous engine deposits can actually cause intake valve sticking when they work up the intake valve stem.
U.S. Pat. No. 5,951,723, Eberhand, Sep. 14, 1999 discloses a method and fuel composition to prevent intake valve sticking, or to reduce or eliminate intake valve sticking comprising a fuel, an effective amount of a hydrocarbyl poly(oxyalkylene) aminocarbamate having at least one basic nitrogen atom and an average molecular weight of about 500 to about 10,000 and wherein the hydrocarbyl group has 1 to about 30 carbon atoms.
U.S. Pat. No. 6,210,452 B1, Su, Apr. 3, 2001 discloses fuel additives effective to control the formation of deposits in internal combustion engines, which comprise carboxylic acid alkoxylates suited for use with nitrogen containing fuel detergents.
International Publication WO 98/12282 A1 discloses a detergent additive composition for diesel fuel that contains a polyisobutylene monosuccinimide in an aromatic hydrocarbon diluent. The detergent additive composition can be used to remove or prevent engine deposits.
U.S. Pat. No. 6,749,651 B2, Carabell et al., Jun. 15, 2004 discloses that a combination of a specific Mannich condensation product, a hydrocarbyl-terminated poly(oxyalkylene) monol, and a carboxylic acid for use in a fuel composition can provide for the control of intake valve deposits.
The present invention, therefore, solves the problem of reducing the amount of deposit formation while reducing or eliminating the intake valve sticking by providing a new fuel composition and composition that can clean up deposits formed and prevent deposits from being formed on the valve stem, which will lead to intake valve stem sticking.